Field of the Invention
The present invention relates, in general, to intravenous catheter insertion devices, and in particular pertains to a coated unitarily constructed composite plastic catheter and cannula arrangement. More particularly, the invention is directed to the provision of a one-piece or unitarily constructed composite plastic catheter and cannula arrangement having a suitably coated needle point which is thereby facilitated for insertion thereof into the vein or body of a patient, whereby the arrangement of an inexpensively produced construction renders the composite catheter and cannula structure of a nature adapted to be readily disposable after only a single use and therefore economically viable, especially for undeveloped or developing countries or regions.
The invention is further directed to novel and unique methods of forming the unitary or single-piece coated composite plastic catheter and cannula arrangement, which are simple to implement and thereby rendering the manufacturing process thereof inexpensive so as to be particularly adapted for economical mass-production techniques for developing countries or regions.
The utilization of clinical apparatus in which pointed hollow needles or cannulae are employed in order to puncture the skin of a patient, and especially catheters utilizing such needles to effectuate venipunctures, is well known in the medical art and is widely practiced by physicians and clinical personnel for the purpose of injecting fluids and drugs directly into the bloodstream of patients. Additionally, during surgical operations or procedures it may be frequently required that whole blood transfusions and parenteral fluids be administered to a patient undergoing such surgical procedures. Basically, as is well known and has been employed for a considerable length of time, the introduction of such fluids into the cardiovascular systems of patients has necessitated the forming of a venipuncture utilizing a hollow rigid needle having a proximal attachment site for a fluid connection which is adapted to interconnect the needle with a source of intravenously administered fluids.
The foregoing method of administering fluids to patients through venipunctures has been subject to some rather serious problems in the administration of fluids to patients in this medical technology. Thus, a primary concern which had to be addressed resided in the inherent rigidity of the needle, the latter of which is normally generally constituted of surgical-quality steel, and while inserted into the vein of a patient, necessitated the needle to be maintained for reasons of safety in a fixed position at the general site of the venipuncture throughout the duration of fluid administration of transfusion, whereby such a procedure could conceivably consume a considerable length of time. In addition to the foregoing, at times it has been necessary to periodically draw blood samples and/or successively administer intravenous fluids to a patient, thus requiring the patient to be subjected to a series of plurality of venipunctures, each administered at a specific time and at different sites on the body, resulting in a relatively traumatic experience to the patient in view of such repeated and somewhat painful and unpleasant venipunctures. Particularly in developing or so-called "third world" countries is it the tendency to reuse a steel cannula, frequently referred to as a steel stylet catheter, many times over. This, notwithstanding the sterilizing and/or autoclaving of such steel stylet in the form of catheters and cannulae, dramatically increases the danger of infections to subsequent patients treated with such reused devices, and also exposes medical or clinical personnel to so-called "needle stick" by a potentially infected cannula upon the latter having been withdrawn from the body of a patient.
Inasmuch as the needle which has been previously positioned in the body of the patient upon forming the venipuncture may have been exposed to infectious agents; for instance, such as a patient infected with Acquired Immune Deficiency Syndrome (AIDS) which is frequently or practically always ultimately fatal in nature, or other dangerous infectious conditions such as hepatitis, notwithstanding the implementation of sterilizing procedures upon withdrawal of the needle from a patient, which in particular in developing countries may be rather rudimentary or crude in nature, there is present the danger or hazard that the clinical personnel may inadvertently or accidentally jab or stick themselves with the used needle after withdrawal from the body of the patient, with the possibility of infection or even death resulting therefrom. Unfortunately, in many developing countries this dangerous aspect which is encountered through the repeated us of such needles is not seriously considered in that rather than contemplating the dangers of infection or potential death resulting therefrom, economic aspects are considered to be of primary concern.
In order to ameliorate or possibly even eliminate the foregoing problems which are encountered in the reuse of steel cannulae or needles; in essence, which may result in extreme discomfort to patients during periods in which such needles remain inserted and endanger the risks of infection by other patients and medical personnel through, the repeated use of the same needles, in the medical technology it has been more recently the practice to introduce a flexible tubular catheter of a low-friction material, such as a silastic or Teflon into the vein of a patient and to permit the catheter tube to remain in such a position over lengthier periods of time for purposes of; for example, periodically administering fluids, including parenteral fluids, blood/plasma transfusions, medications in liquid form and also for the collection of blood samples and the like. In this manner, the previously encountered trauma, extravasation, and infiltration caused by repeated venipunctures have been largely avoided, and the danger and discomfort to a patient of leaving a rigid needle in the body for a prolonged period of time has been generally overcome. Thus, in order to position the distal end of such a flexible catheter tube within the body cavity of a patient, such as a vascular cavity or vein, there is normally employed a cannula or hollow sharp-tipped needle for the purpose of forming the venipuncture. Thereafter, the flexible catheter tube, which is telescopically and slidably coaxially mounted on the outer circumference of the cannula or hollow needle so as to extend sleeve-like thereabout is advanced along the length of the needle into the vein subsequent to the needle having formed the venipuncture. Thereafter, the needle is adapted to be withdrawn from the interior of the catheter tube, while permitting the latter to remain within the body of the patient at the site of the venipuncture, and the needle is suitably discarded.
Although the foregoing utilization of flexible catheter tubes and cannulae of which the former is essentially constituted of a plastic material and the latter of steel, incorporates structure for retracting the withdrawn needle into a protective environment, such as a safety housing or the like, the overall construction is relatively complex and, especially in developing or so-called "third world" countries, may be considered too expensive to be considered a viable economical alternative to the multiple reuse of steel cannulae or stylets.